Very good and very early description of an ion drive system for propulsion.

Nine slender sunships lay at the side of the wide, high-fenced field, just in front of their sheds. In the brilliant morning sunlight they scintillated like nine huge octagonal ingots of polished silver.

These war-fliers of the Moon Patrol were eight-sided, about twenty feet in diameter and a hundred long. Built of steel and the new aluminum bronzes, with broad vision panels of heavy vitrolite, each carried sixteen huge positive ray tubes. These mammoth vacuum tubes, operated at enormous voltages from vitalium batteries, were little different in principle from the "canal ray" apparatus of some centuries before. Their "positive rays," or streams of atoms which had lost one or more electrons, served to drive the sunship by reactionóby the well-known principle of the rocket motor.

And the sixteen tubes mounted in twin rings about
each vessel served equally well as weapons. When focused on a point, the impact-pressure of their rays equaled that of the projectile from an ancient cannon. Metal in the positive ray is heated to fusion, living matter carbonized and burned away. And the positive charge carried by the ray is sufficient to electrocute any living being in contact with it.